I think the problem here is that the loan deal was a two year one without break clauses, so we can't buy him off of Juventus (until Summer 2022 anyway).
What makes me think that Atalanta have stuck to their guns? Normality and history.... We make an offer, Atalanta turn it down, we make another offer, Atalanta turn it down, we ask them what price they want for him, they tell us, we make another offer (well under that), Atalanta turn it down, we increase it a bit, etc, etc.
It would be rare for a club to name their price and then turn down a bid for that amount and state a higher price, especially as player and agent would be aware and become very frustrated at that sort of behaviour with the chance of increasing their income. The only time that really happens is when the asking price bid comes in right at the end of the window when there is no time for the selling club to secure a replacement.
Based on probability we just haven't got to Atalanta's asking price yet and, frustratingly for us, they're not showing any signs that they will compromise and lower it (at least not lower it to whatever amount that we are bidding anyway).